THE history of nations illustrates the law of centripetal force, as small separate communities pulled together toward a center. Today a kind of centrifugal force has reversed the political direction, causing nations to fly apart.
Small countries want to be smaller. Czechoslovakia is only the latest nation to threaten, by recent elections, to split into parts. Yugoslavia has violently splintered, its internal wars costing not only innocent lives but buildings and works of art that, ironically, attest to an exquisite civilization.
In addition, the former Soviet empire is tearing itself into ever smaller bits of ethnic identity. In Afghanistan the rebels who once united against that Soviet Union now fight among themselves.
This centrifugal force, whirling apart nations into local tribes, has not spared the United States. A group of Kansans, reluctant to accept urban blight as their problem - particularly at tax time - have threatened secession. And northern Californians are not so sure they should belong to the same state as southern Californians.
Within many communities, smaller constituencies appear to see it as their destiny to stress their separateness. Even the daily student newspaper at the University of Massachusetts yielded to demands that each minority should be represented by separate editorial territory within the paper, the coverage to be provided by a reporter chosen by each minority.
As all this separating is going on, the Earth Summit at Rio has signaled that what happens to air, water, and forests in the remotest corner of the earth will sooner rather than later affect every living being on it. Geopolitically speaking, we are one community.
E. M. Forster's novel "Howards End" made famous the motto, "Only connect." The new film adaptation of the novel is reviving at an opportune time Forster's call to diverse human beings to build bridges across their differences.
"Only connect" is an ideal rather than a program, but it sets the right tone for a moment in history when every challenge on the global agenda requires more and more cooperation - better and better bridge-building.